There is an immunoassay apparatus that performs measurement on a test substance using an antigen-antibody reaction. As a technique of enhancing sensitivity of the measurement by the immunoassay apparatus, there is an immune complex transfer method (see, for example, Japanese Patent Application Publication No. H01-254868 (Patent Literature 1)).
In the above technique disclosed in Patent Literature 1, an immune complex of the test substance and a labeled antibody is generated on a carrier using the antigen-antibody reaction. After a releasing reagent is input to a measurement specimen including a conjugate of the immune complex and the carrier, the immune complex released from the carrier is extracted from the measurement specimen (a procedure 1). With a procedure 1, the labeled antibody nonspecifically adsorbed by the carrier is removed. Subsequently, immune complex measurement is performed using the extracted immune complex (a procedure 2).
In the immunoassay performed using the immune complex transfer method, a pretreatment apparatus that carries out the procedure 1 and an immunoassay apparatus that carries out the procedure 2 need to be separately used. There is a need for a single apparatus capable of performing the immunoassay.